Oil cracking apparatus



June 14, H THOMAS OIL CRACKING APPARATUS Filed June 8. 1927 2 Sheets-Sheet f/em/z/ Mamas June 14, 1932. H THOMAS 1,863,173

OIL CRACKING APPARATUS Filed June 8, 1927 2 Sheets-Sheet 2 Patented June 14, 1932 UNITED STATES PATENT HENRY THOMAS, OF RIDLEY PARK, PENNSYLVANIA, ASSIGNOR TO SUN OIL COMPANY,

OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION F NEW JERSEY OIL CRACKING- APPARATUS Application led June 8,

rlhe present invention relates to those apparatus for racking hydrocarbon oils which comprise a tube, or series of tubes. for heating oil under high pressure to a temperature considerably above a minimum cracking teinperature (say 80043000 F.) and a chamber, in series with the tube or tubes, in which the cracking under the saine high pressure is completed and from which the cracked hydrocarbons escape into towers wherein the superatmospheric pressure is greatly reduced or removed and wherein the lighter cracked hydrocarbons. are separated from the heavier cracked hydrocarbons. Such chambers are differently designated as cracking tanks, soaking drums or reaction cham- ,ers. The term reaction chamber is apt in that it defines whatever action may occur in the tank or drum. The hydrocarbons undergoing cracking are usually introduced at or near one end ot the chamber and escape from or near the other end of the chamber through a valve, which regulates `the rate of outflow and also maintains the proper pressure on the chamber and the heating and cracking tubes.

Because otl the high pressure and high temperature that are maintained in the chamber, and because, also, of the factor of safety which the high temperature requires and the fatigue of the metal, these chambers are limited in size. This limits the size of the unit of which the chambers ,forms a part. The capacity of the whole cracking unit is therefore limited.

It is also not possible, with such a unit, to continuously carry on the cracking operation for longer than a limited time. The reason for this is that carbon, which is a resultant 'product of the cracking7 gradually settles out in the chamber and ultimately accumulates to such an amount as to necessitate the stoppage of the operation and the cleaning out ofthe chamber. The length oit' the run, therefore, depends very largely on the carbon-carrying capacity of the chamber, and the size ot the latter is limited by the factors above explained.

It has been proposed to provide a. plurality of reaction chambers to be fed from a common series of heating and cracking tubes. This arrangement would obviousl enable the length of the run to be multiplied proportionately to 'the increase in number of chambers; or the capacity of the unit could be multiplied to the same degree with no increase in length of run; or both the capacity of the unit and the length of the run could be increased.

It is a fact, however, that it is di'llicult to attempt to yoke a plurality of reaction chainbei's to a single heating and cracking pipe or pipe series. The mere provision of brauch pipes with valves to control the flow has been tried and iound troublesome, uncertain and dangerous. It should be borne in mind that the mixture ot' hydrocarbons undergoing cracking, as it leaves the cracking tube and enters the reaction chamber, is, if heated to, or even considerably below, 900O F., above its critical temperature and therefore in gas phase, and even though heated to c low its critical temperature and therefore largely in liquid phase, the mixture {iows into the reaction chamber at high speed and under ver? high temperature and its flow cannot be controlled by the many obvious expedients which would be successful in controlling liuid flow under lower temperatures and at lower velocities.

In the attached drawings l have shown a construction whereby the tlow can be accurately and safely controlled and which is operated successfully on a commercial scale.

Fig. l is a plan view of the apparatus.

Fig. 2 is an end view.

Fig. 3 is a detail view box.

Fig. 4 is an end view of a modification.

Fig. 5 is a perspective view of the distributing box shown in Fig. 4..

The discharge end, or an extension from the discharge end, oi a cracking tube a which may be in series with a preheating tube, not shown) is connected to a special junction box fitting Zi. The form of the box shown approximates that of a cube. Preferably (if only two reaaction chambers are provided) it is a six-sided box, one end of which is connected with pipe a, while two adjacent sides are connected with pipes c and d, which are i `small spa-ce between them,

connected respectively with the end portions of two reaction chambers h and z', extending horizontally and in parallelism with each other and with the inlet pipe a. The pipes c and l extend at equal angles to a vertical plane passing through the axis of the inlet pipe a, which is midway between the two chambers. In the drawings, pipes c and d are shown asy extending at angles of approximately 450 to the vertical plane; but successful operation does not preclude a substantial variation from this angle. Since the chambers are very heavy and are fixed in their position, thel arrangement shown and described provides for the necessary movement due to expansion and contraction as well as for the equal division of thefhydrocarbon stream.

Box b is also provided with three plugs e, f and g located respectively on the end of the box opposite inlet pipe a and on the sides of the box opposite outlet pipes c and CZ.

The box need not be of the shape shown even if connections are provided to only two reaction chambers and would be of different shape if more than two reaction chambers were used.

The high velocity of the entering oil is not only no hindrance to successful operation of the distributing device shown but is probably necessary to its successful operation.`

rlhe hydrocarbon stream, traveling through pipe a at a velocity (say) of 8 to 10 feet per second, strikes the dead end of the box fitting and divides itself automatically into two streams of equal volume that shoot through the pipes c and d into the chambers L and z'.

This operation is more or less dependent upon the provision that l have made for controlling the outflow of hydrocarbons (in whatever condition they are, whether liquid and vapor, or gas, when they leave the reaction chamber). Each outlet line is equipped with a special type of valve. After a reaction chamber has been in luse for some time,

' the valve becomes slogged with carbon near the outlet from the chamber, and it is necessary to provide a boring device for removing the deposit while the system is in operation and under pressure. Such boring devices are known and in use. In the structure shown in the drawings, the outlet valves are so positioned as to allow two chambers to be placed side by side, with a comparatively and yet leave the necessary room for the boring-out equipment, which must of necessity occupy considerable space. If onlytwo reaction chambers are used, it is possible to place the outlet lines and the boring-out equipment on the opposite sides of two chambers. If, however, morethan two chambers are placed side by side, as, for instance, where there are two units with two chambers each, or two units with three chambers each, obviously only two of the outlet lines could be placed on the outside.

In my construction the outlet pipe sections m and n, equipped with special valves 0 and p, are placed on opposing sides of the reaction chambers 7L and somewhat above a horizontal plane intersecting the axes of the chambers, and extend therefrom at relatively sharp angles to the horizontal and at relatively wide angles to ,the'verticaL rlhe two outlet pipe sections also extend along different, but not widely spaced-apart, vertical planes extending perpendicularly to the axes of the reaction chambers. Diverging from pipes m and n, and constituting extensions thereof, are two pipes r and s, which communicatewith a common pipe t leading to the tower or towers (not shown) for yseparating the gasoline constituents from the heavier constituents of the cracked mixture of hydrocarbons. Pipes m, n are equipped with pressure gauges c, c, at substantially distances from valves o and p and from the union of such pipes with pipe t and preferably, but not necessarily, midway between said valves and pipe t. Such pressure gauges, or equivalent devices, function practically as orifice meters to measure the pressure drop on the lines and indicate to the operator the relative flow through the lines, so that he can adjust valves o and p, when necessary, to equalize the flow 'from the chambers.

The reaction chambers should be equipped with pressure gauges w, w, which can be used in conjunction with pressure gauges, c, c, to show the conditions in the inflow lines to the chambers and outflow lines from the chambers to determine whether they are becoming clogged with carbon and thus obstructing the free flow of hydrocarbons into the chambers.

rThe boring-out device y, y, are positioned to engage the'ends of pipe sections m and fa, and extend in alignment therewith, so that each is in a position to be conveniently opera-ted without interference with the other boring-out device.

`Without provision for measuring and regulating the outflow from the two reaction chambers, the conditions of volume, rate of travel, pressure and other factors within the two chambers may be so unequal and uncertain that-the described operation of the feed to the chambers, and particularly the sub- Die theunit comprises a single reaction chamber, the construction is capable of operation without 'the use of any other valves whatever. rihis feature is of great importance, as such valves, although they have been deemed necessary in multiple reaction chamber constructions, are a main source of the trouble, uncertainity and danger incident, heretofore, to the attempted provision of. multiple reaction chambers.

In Figs. and 5 is shown a preferred adaptation of my invention to a set of three reaction chambers 11, l2 and 13 The arrangement ol the two end chambers l1 and 13, of the inlet pipe 2() to the distributing bor; 15 and of the branch pipes 21 and 23 to the end chambers 11 and 13, is essentially the same as the arrangement of chambers /z and z', box h, inlet pipe a and branch pipes c and (l, shown in Figs. 1 and 2. The additional, or middle, chamber 12 is arranged at a level below that oi' chambers 11 and 13 and the branch pipe 22 extends downward in the same vertical plane through which inlet pipe 2O entends, this plane bisecting chamber 12 lengthwise and being midway between and parallel to chambers ll and 18. The junction box 15 is preferably hexagonal in cross-section, coinorising two end walls and sii: sides. Inlet pipe 2O extends into one end wall or" the box, and outlet pipes 21, 22 and 23 connect with three of its sides. The boX is oriiiced on the other end wall and the other three sides and in line with respective pipes 20, 21, 22 and the orifices being closed by plugs 30, 3l, 32 and 33.

Having now fully described my invention, what .I claim and desire to protect by Letters Patent is: l

l. In an oil cracking plant, the combination, with an inlet pipe for highly heated hydrocarbons, of a plurality of reaction chambers, branch pipes communicating respectively with the reaction chambers, and a junction boX provided with an inlet communicating with the inlet pipe and outlets communicating with the branch pipes, and removable plugs in the walls of the inlet boX respectively opposite the said inlet and outlets.

2. In an oil cracking plant, the combination, with an inlet pipe :tor highly heated hydrocarbons, of a junction box into which said pipe discharges, two horizontal reaction chambers arranged in parallelism on op osite sides of the junction box, and two branch pipes connecting the junction bei; with the respective chambers, said branch pipes extending at substantially equal angles to, and on opposite sides of, a vertical plane extending between, and parallel to the direction of extension ot, the two chambers.

B. In an oil cracking plant, the combination, with an inlet pipe for highly heated hydrocarbons, of a junction box into Which said pipe discharges, two horizontal reaction chambers arranged in parallelism on opposite sides of the junction box, and two branch pipes connecting the junction box with the respective chambers, said branch pipes extending at substantially equal angles to, and on opposite sides of, a vertical plane extending between and parallel to the direction of ei;- tension of, the two chambers, the end of the inlet pipe communicating with the junction box extending in said plane and substantially bisecting the angle between the two branch pipes.

i. In a cracking plant, the combination with a plurality of horizontally extending reaction chambers arranged side by side, ci" a common supply pipe, branch pipes coinmunicating with the supply pipe and with the respect-ive reaction chambers, outlet pipes for cracked hydrocarbons comprisingl end sections extending from opposing sides oli adjacent reaction chambers obliqucly upward at relatively sharp angles to the horizontal and at a relatively wide angle to the vertical, manually regulable valves on said end sections, and boring-out devices connected and aligning Vith said valve-d end pipe sections.

5. In a cracking plant, the combination with a plurality ot horizontally extending reaction chambers arranged side` by side, oi a common supply pipe, branch pipes coinniunicating with the supply pipe and with the respective reaction chambers, outlet pi pes for cracked hydrocarbons con'iprising end sections extending toward one another along radii of two adjacent tanks above and at acute angles to a horizontal plane intersecting the aXes of both tanks and extending also in vertical spaced-apartplanes perpendicular to the axes of the tanks, regulable valves on said end pipe sections, and boring-out devices connecting and aligning with said valved end pipe sections.

6. In an oil cracking plant, the combination with a plurality of reaction chambers, of a valveless junction box, an inlet pipe connected with and adapted to convey highly heated hydrocarbons to the junction box, a plurality of valveless pipe sections connecting the junction box with the respective chambers and tending to equally divide the flow of hydrocarbons to the chambers, and means at the outlet end of the reaction chambers to enable the operator to visually ascertain and manually substantially equalize the comparative conditions in the reaction chamber and thereby, without manual regulation of the supply to the respective chambers, insure a substantially equal division of the hydrocarbon supply thereto.

7. In an oil cracking plant, the combination with an inlet pipe for highly heated hydrocarbons, of a junction box into which said pipe discharges, two horizontal reaction roo chambers arranged in parallelism on opposite sides of the junction box, a third horizontal reaction chamber arranged below the junction box and between, and in parallelism iwith, and below the level oi, the other two reaction chambers, and branch pipes connecting the junction box with the respective chambers. f

8. ln an oil cracking plant, the combination with an inlet pipe for highly heated hydrocarbons, ot a junction box into which said pipe discharges, two horizontal reaction chambers arranged in parallelism on lopposite sides oi the junction box, a third hori- Zontal reaction chamber arranged below the junction box and between, and in parallelism with, and below the level of, the other two reaction chambers, vand branch pipes connecting the junction box with the respective chambers, the branch pipe connecting the junction box with the middle chamber extending'downward in substantially a vertical plane extending between, and parallel to the direction of extension of, the end chambers, and the other two branch pipes extending at substantially equal angles to, and on opposite sides of said plane.

9 ln an oil cracking plant, the combination, with an inlet pipe for highly heated hydrocarbons, of a plurality of reaction chambers, a junction box into which said inlet pipe discharges, and a plurality of pipes radiating from the junction box and communicating with the respective chambers, said box havving two end walls and sides equal in number to twice the number of reaction chambers, said inletv pipe discharging into one end wall and the other pipes discharging from side walls, and removable plugs in the walls of the inlet box respectively opposite the walls from which said pipes extend.

l0. In an oil cracking plant, the combination, with an inlet pipe for highly treated hydrocarbons, of a junction box into which said pipe discharges, two horizontal reaction chambers arranged in parallelism on opposite sides of the junction box, and two branch pipes connecting the junction box with the respective chambers, said branch pipes extending at substantially equal angles to, and on opposite sides of, a vertical plane extending between, and parallel to the direction of extension of, the two chambers, outlet pipes for cracked hydrocarbons comprising end sections extending from opposing sides of adjacent reaction chambers obli quely upward at relatively sharp angles to the horizontal and at a relatively wide angle to the vertical, and manually regulable valves on the outlet pipes.

ll. In a cracking plant, the combination with a plurality of reaction chambers, of a common supply pipe for highly heated hydrocarbons, branch pipes for conducting said hydrocarbons :from the supplyl pipe to the respective chambers, means tending to equally distribute said hydrocarbons from the supply pipe to the branch pipes, outlet pipes for cracked hydrocarbons from the respective chambers, pressure gaugesV on the outlet pipes beyond Vthe respective valves for measuring the relative pressure drops and the relative flow through the'ditferent outlet pipes, and valves controlling the outlets from the respective tanks to the respective outlet pipes, said valves being manually regulable to re-establish equality of flow through the outlet pipes in case said pressure gauges indicate dilTerent pressures.

l2. In a cracking plant, the combination with a plurality ot reaction chambers, of a common supply pipe for highly heated hydrocarbons, branch pipes for conducting said hydrocarbons from the supply pipe to the respective chambers, means tending to equally distribute said hydrocarbons from the supply pipe to the branch pipe, outlet pipes for cracked hydrocarbons from the respective l chambers, manually regulable valves controlling the` respective outlets, pressure gauges on the reaction chambers, adapted to indicate the pressures in the respective tanks, pressure gauges on the outlet pipes beyond said pipes adapted to indicate the relative pressure drops and relative flow through said pipes, thereby enabling the operator to so adjust said valves as to establish substantial equality of pressures in the reaction chambers and thus insure substantially equal supplies of hydrocarbons to the chambers by the disil' tributing means.

In testimony of which invention, l have hereunto set my hand, at Marcus Hook, Pa., on this 3d day of June, 1927.

HENRY THOMAS.

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